With the rapid development of microelectronic technology, computer peripherals have been substantially improved and highly diversified. Nowadays, computers are used not only for word processing and web browsing, but also for the users to enjoy the replay of high-quality audio and video files, play online 3D games, or execute complicated application programs. As the sizes of files, be they high-quality audio/video files or other digital data files, must increase with the degree of data complexity and precision, high-capacity hard disks have been essential to almost all computer products.
Currently, a hard disk drive (HDD) can store up to several terabytes of electronic data, but the mechanical structure of such an HDD makes it difficult to increase its read and write speeds to levels comparable to those of a central processing unit (CPU). Moreover, due to their high power consumption and low shock resistance, HDDs are not suitable for use in mobile electronic devices. In view of the above, the industry has conducted extensive research and development in search for new storage devices, among which solid-state disks, or solid-state drives, (SSDs) are the most promising. An SSD is a computer data storing device based on a non-volatile memory (e.g., a flash memory). The principle of the SSD technology is to form a storage device by connecting a plurality of memories (e.g., NAND memories) together in conjunction with an appropriate control chip and related circuits. In terms of specifications, most SSDs are manufactured in the same sizes as HDDs, the most common sizes being 1.8″, 2.5″, and 3.5″, and this is because SSDs are typically used as a substitution for HDDs. As for the connection interface between an SSD and a computer, SATA2 is presently the most popular, but some SSDs use other connection interfaces such as IDE, SATA, SATA3, 1394, USB, and PCI-E. The memories for use in SSDs can be generally divided into two major categories: multi-level cell (MLC) and single-level cell (SLC); nevertheless, the newly developed triple-level cell (TLC) memory is also eligible. As far as current technology is concerned, MLC-based SSDs are less costly but have lower write speeds and shorter service lives than SLC-based SSDs.
In contrast to HDDs, SSDs are advantageous in that they produce no noise, have lower power consumption, are more resistant to shock during reading and writing, generate less heat, and can be more easily made lightweight; therefore, SSDs are perfect for use in portable electronic devices. In addition, according to test results, SSDs have read speeds approximately more than two to three times as high as those of HDDs and write speeds more than 1.5 times as high. Given that HDDs have become a bottleneck for system performance, SSDs are indeed a decent solution. However, due to the fact that the cost per megabyte of either a non-volatile memory or a volatile memory is far higher than that of an HDD, the lofty prices of high-capacity SSDs have made it impossible for an ordinary user to replace all the HDDs in use with SSDs.
As a solution, the hybrid drive emerged. The hybrid drive, based on a technology generally known as HDDBOOST, essentially includes a control device installed in a computer and respectively connected to an HDD and an SSD. By means of the control device, the computer can read data from either drive or simultaneously write data into both drives. While this technology can boost data read speed to some degree, its data writing process leaves much to be desired. More particularly, in order to achieve data synchronization between the HDD and the SSD, the control device is configured to write data into both drives at the same time, which, however, hinders significant improvement of the computer's overall performance.
As a hybrid drive is merely a hardware structure, a corresponding software or system is required for writing data correctly into or reading data out of the hybrid drive, and the related processes are critical to the performance of the hybrid drive. Hence, the issue to be addressed by the present invention is to design a system and method for increasing the read and write speeds of a hybrid drive.